This proposal addresses the development of a Nuclear Magnetic Resolution (NMR) method for quantitative and instantaneous blood flow measurement at selected regions of the NMR image. The possibility of obtaining regional perfusion characteristics in addition to the anatomical structure as provided by the non-ionizing NMR imaging methods would greatly increase the utility of this modality for the evaluation of any cardiovasculr function or disease. To accomplish this goal we propose five tasks: 1. Continue the theoretical development of a method we have developed for measuring the instantaneous velocity at specific regions. A patent application has been filed for this method. 2. Use computer simulation to derive a better understanding of the interactions of the numerous factors affecting this method. This simulation, coupled with the theoretical development of tasks (1), will provide a strong foundtion forin viro and in vivo flow measurements. 3. Evaluate the performance and the difficulties of using the proposed method by controlled in vitro flow experiments. 4. Test the developed methods by performing in vivo flow measurements and imaging on rabbits. 5. Further evaluate the method by conducting in vivo flow measurements and imaging on human limbs. All flow experiments will be performed on a 3l cm bore, l.9 Tesla NMR system. The system has been engineered for significant hardware and software flexibility and is ideally suited for this development.